Working instruments of the type of the present invention are used in conjunction with resectoscopes, e.g. in urology or gynaecology. For this purpose, the working instruments are inserted into the resectoscope and then advanced through orifices and channels of the body, e.g. the urethra, to the desired treatment site, e.g. the prostate.
Working instruments of this type consist of a long actuator rod, which can be attached in the sliding body of a resectoscope with their proximal end. On its distal end, the working instrument comprises a working device, e.g. a cutting loop to which a HF current can be applied, a cold knife, a curette or other devices known from the state-of-the-art, which allow the surgeon to perform the desired treatment, e.g. resection of the prostate, at the treatment site.
Modern resectoscopes are provided as continuous irrigation resectoscopes, in which the continuous irrigation of the operative field provides a clear view of the operative field to the surgeon. For this purpose, the resectoscopes comprise two separate channels, one of which is provided for the supply of irrigation fluid and the other is provided for the return of the contaminated fluid. A proven design providing these two channels are double-sheath endoscopes, such as shown e.g. in DE 100 42 097.4. In the following, the invention is illustrated in more detail as an example of a double-sheath endoscope without limiting the scope of the invention to this particular design of endoscope.
The resectoscope shown in DE 100 42 097.4 consists of an external and an internal sheath, a main body, a working instrument with cutting loop and guiding sleeve, a guiding tube with end-piece, a sliding body, and a telescope with eye-piece. For assembly, the telescope is inserted from a proximal end into the guiding tube, which is firmly connected to the main body and on which the sliding body is borne such that it can be displaced in an axial direction. Then, the working instrument with its attachment area leading is advanced from a distal end through a bore in the main body to the sliding body, and attached in the sliding body. During the advancement of the working instrument, the guiding sleeve slides over the telescope. Finally, the internal sheath, which is provided in the shape of an elongated tube, is pushed over the telescope and the working instrument, and coupled to the main body.
The external sheath, which is also provided in the shape of an elongated tube and may have a filling rod inserted into it, is introduced into the body of the patient by the surgeon. After removal of the filling rod, the resectoscope, assembled as described above, is then introduced through the hollow external sheath and the external sheath is also coupled to the resectoscope. At this point, the surgeon can commence the operation.
One problem associated with the type of assembly illustrated above is that the working instrument must be held with the fingers while it is being inserted through the bore in the main body and until it is locked in the sliding body. The working instrument is held either at the actuator rod, the guiding sleeve or at its distal end. However, neither of these areas possesses particularly good handling features, especially the distal end area of the working instrument which usually is not particularly resistant to the impact of forces applied to it. Consequently, there is a risk of damaging the working instrument. Moreover, there is a risk of injury if the working instrument bears a sharp-edged working device.
DE 101 22 465.6 shows a double-shaft resectoscope with a cutting loop as the working device, whereby the cutting loop has a larger diameter than the internal sheath. This means that the working instrument can no longer be guided through the internal sheath without damaging the cutting loop. For this reason, the assembly of this resectoscope must deviate from the procedure detailed above in that the internal sheath is pushed over the telescope and connected to the main body first. Only thereafter it is possible to insert the working instrument with its attachment area leading from a distal end through the internal sheath.
The internal sheath of the design shown in DE 101 22 465.6 is only slightly shorter than the working instrument. Therefore, almost the entire working instrument is inside the internal sheath during its insertion such that it can be grasped only at its distal end area, on which the cutting loop is arranged also. The handling problems described above are even more pronounced in this design.
It is therefore an object of the present invention to provide a working instrument, which simplifies the insertion into a resectoscope and remedies the described problems through the use of simple means.